The “union wage premium” — the amount a union worker makes in wages and salary above a similar nonunion worker — is often used to highlight the potential value of joining a union. Unions claim that if workers unionize, their wages will increase, because allegedly the average union worker makes more than the average nonunion worker. If this were universally true, it seems like a compelling argument for enrolling in a union. However, the decline in union membership rates over the last several decades shows that an increasing number of workers have not been persuaded to join existing unions or organize new ones, suggesting that they are not convinced that becoming a union member will automatically boost their pay.

Some still maintain that union members earn significantly more, on average, than nonunion workers: the American Federation of Labor and Congress of Industrial Organizations union says that “union workers’ wages are 27 percent higher than their nonunion counterparts” and the U.S. Secretary of Labor claims that union workers make $950 per week compared to nonunion workers’ $750 per week. But these statistics are based on a relatively simplistic view of the data. As this paper will demonstrate, there are significant challenges to using official government data to estimate the size of the union wage premium.